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The present invention relates generally to tube sets for use in supplying fluids such as food and medicine to the stomach of a human or other subject through a surgically constructed opening, and more particularly to a gastrostomy tube set having an improved coupling arrangement between a pair of tube assemblies of the set.
It is conventional to provide a gastrostomy tube set having a pair of tube assemblies, one of which is a delivery assembly adapted to remain in place in the stomach of a subject for an extended period of time, e.g. several months, and the other of which is a single-use supply assembly adapted to be coupled to the delivery assembly for a relatively short time, e.g. 12 -24 hours. This known arrangement obviates the need for frequent replacement of the delivery assembly, while enabling the use of disposable, single-use supply assemblies for each infusion of nutrients and/or medicine into the stomach.
In a known tube set, the delivery tube assembly includes an elongated, flexible tube formed of silicone or the like and presenting a central fluid passage for permitting fluids to be introduced into the stomach of a subject. The tube also includes a relatively small-diameter second passage extending along a side of the fluid passage, and a sleeve of expandable material surrounds the tube adjacent the inner end thereof and is in communication with the second passage such that air can be introduced to the sleeve through the second passage to inflate the sleeve during placement of the delivery set. The outer end of the tube is formed into a hub or termination presenting an infusion port communicating with the central passage and an inflation port communicating with the second passage. A valve is disposed in each passage adjacent the port, and controls the introduction of fluids to the tube. In order to inflate the sleeve of the tube, the valve in the second passage is opened and air is forced into the second passage. Likewise, the valve in the central passage must be opened in order for nutrients or medicine to be supplied to the central passage.
The supply assembly of the known tube set includes a supply tube formed of silicone or the like and presenting a central fluid passage for permitting fluids to be supplied to the delivery tube assembly. In addition, the assembly includes a connector for permitting the assembly to be coupled with the delivery assembly and for shifting the valve in the central passage of the delivery tube to the open position. The connector is formed of a relatively rigid medical grade synthetic resin, and includes a male element sized for receipt in the infusion port of the delivery tube, and a radially protruding lug.
The infusion port of the delivery tube is circular, and includes a radially extending notch that is specially adapted to receive the lug of the connector. A circumferential groove extends around the inside of the central passage of the delivery tube just inboard of the infusion port, and communicates with the notch to receive the lug and enable the connector to be rotated about the longitudinal axis of the male element after the lug has been inserted into the notch, locking the connector in place on the termination of the delivery assembly. As such, the connector can only be inserted into the infusion port in a single orientation, and can then be rotated about the axis of the male element to lock the connector in place. Removal of the connector also requires that it first be rotated to a position in which the lug aligns with the notch before being withdrawn.
Although known gastrostomy tube set constructions perform their intended functions, numerous drawbacks and technical problems exist. For example, in the known constructions, the infusion valve is spaced from the infusion port by a distance of several millimeters, and the groove for receipt of the lug is inboard of the infusion port, creating a void or cavity within the central passage inboard of the port. This cavity is a collection point for fluids and bacteria, and is difficult to clean and disinfect. In addition, conventional infusion valve constructions do not provide a good seal against the male element of the connector during infusion, creating the possibility of leakage.
It is an object of the present invention to solve the technical problems left unaddressed by the prior art, and to provide a gastrostomy tube set that is easy to use, easy to clean, presents a lower risk of infection than conventional constructions, and provides a better seal between the supply and delivery assemblies during infusion.
In accordance with these and other objects evident from the following description of a preferred embodiment of the invention, the gastrostomy tube set of the present invention includes a delivery assembly having a first tube adapted for placement in the stomach of the body and presenting an outer end, a termination connected to the outer end of the first tube and being adapted for placement against the external surface of the body, and a valve assembly disposed in the fluid passage of the termination and including a housing and a valve body disposed in the housing. The housing includes an elongated throat that protrudes from the termination and presents an infusion port communicating with the fluid passage, and at least one circumferentially extending flange that protrudes radially outward from the throat. The tube set also includes a supply tube assembly constructed of a second tube presenting a distal end to which a connector is secured. The connector includes an elongated tubular male element defining a longitudinal axis and being sized for receipt in the infusion port, and a side wall extending generally coaxially with the male element. The side wall presents a lug that protrudes radially inward toward the male element, and the connector is coupled to the valve assembly by orienting the connector with the lug displaced circumferentially from the flange, inserting the male element into the infusion port to shift the valve body to the second position, and rotating the connector about the longitudinal axis of the male element so that the lug engages the flange to prevent the connector from being pulled axially from the termination.
By providing a construction in accordance with the present invention, numerous advantages are realized. For example, by providing a valve assembly and connector in accordance with the present invention, it is possible to easily and securely couple the supply and delivery tubes of the set together. In addition, by providing an external flange on the housing of the valve assembly rather than an internal groove as is found in conventional constructions, the infusion port site is exposed for cleaning and disinfecting, and presents less risk of infection to the subject.
Preferably, the flange of the housing defines an outer diameter that is greater than 7.2 mm, which corresponds to the maximum diameter of the threaded locking collar of a conventional Luer fitting. As such, the delivery assembly of the tube set does not couple with a conventional Luer fitting, providing protection against the infusion of any fluids other than those specifically prescribed for introduction through the tube set into the stomach of the subject.